Method for obtaining water-soluble polymers, resulting polymers and uses thereof

ABSTRACT

A method of obtaining homopolymers and/or copolymers in aqueous solution by the use of phosphorous acid and/or its salts or sodium hypophosphite and by neutralisation during the polymerisation of the ethylenically unsaturated monomers by the continuous addition, first of all, of bases such as sodium hydroxide, potassium hydroxide or lithium hydroxide and then bases of alkaline earths such as calcium hydroxide, magnesium hydroxide, calcium oxide or magnesium oxide. The polymers obtained by the said method and uses thereof.

The invention relates to a novel method of obtaining homopolymers and/orcopolymers, in an aqueous solution of monoethylenically unsaturatedmonomers such as acrylic and/or vinyl monomers, making it possible toobtain directly usable polymers.

The invention also relates to the homopolymers and/or copolymersobtained by the said method as well as their use as an aid to thegrinding and/or dispersion in aqueous solution of mineral materials, oras a sequestring agent or mineral scale and/or incrustation inhibitor inparticular on the heat transfer surfaces of industrial or domesticinstallations or as a fluidising agent for aqueous solutions based onsoft or saline water normally used as drilling fluids in the fields ofcivil engineering, building, public works, petroleum prospecting orextraction or as a zeolite suspension stabiliser and as an antiscalingagent or as a water retaining agent in the paper making industry or alsoas builder or co-builder in detergent compositions or finally asdispersant which does not destabilise the chlorometric rate of thehypochlorite compositions in the detergent formulations containing it.

Finally, the invention relates to the said aqueous solutions of mineralmaterials which are stable over time and have a high concentration ofmineral materials as well as their use in the field of paper, paint,detergent and cleaning formulations and any other field using the saidsuspensions such as in particular ceramics or drilling fluids.

For a long time already persons skilled in the art have known variousmethods for homopolymerising in solution acrylic and/or vinyl monomerssuch as in particular acrylic acid, methacrylic acid, maleic anhydrideor acrylamide as well as for copolymerising, in solution in water,acrylic acid with other monoethylenically unsaturated monomers such asfor example maleic anhydride, itaconic acid, acrylamide or acrylamidomethyl propanesulfonic acid.

Thus the patents FR 2 751 335, EP 0 405 818, EP 0 618 240, U.S. Pat. No.4,621,127 and EP 0 792 890 describe methods of polymerising acrylicacid.

Likewise a person skilled in the art has available U.S. Pat. No.4,301,266, which describes a method of manufacturing acrylic acidpolymers having the drawback of requiring the use of a solvent of theisopropanol type and requiring work under pressure, and distillation inorder to eliminate the solvent.

Finally, persons skilled in the art also know the patents FR 2 539 137,EP 0 542 644 or EP 0 516 656 teaching that neutralisation of acrylicpolymers with alkaline earths makes it possible to obtain agents for thegrinding of calcium carbonate by the wet method, these suspensions beingparticularly stable over time.

However, all these polymerisation techniques well known to personsskilled in the art require a step of neutralisation of the polymersolution obtained in acid form or partially neutralised subsequently tothe polymerisation reaction, then obliging the producer of thesepolymers either to equip himself with equipment specific to thepolymerisation and another type of equipment peculiar to theneutralisation reactions or to occupy the polymerisation reactors for alonger time, which has the consequence of reducing the productivity ofthe installation and therefore increasing the cost of the products.

Confronted with these various drawbacks, which cannot fully satisfy aperson skilled in the art, the Applicant has found, surprisingly, thatdispersing agents and/or high-efficiency grinding aids of mineralmaterials can be obtained by the polymerisation of acrylic acid andethylenically unsaturated monomers using phosphorous acid and/or itssalts or sodium hypophosphite provided that, during the polymerisationprocess, neutralisation agents consisting of alkaline earths areintroduced into the reaction medium after the partial neutralisation ofthe monomer or monomers by means of an alkali ion such as in particularsodium, potassium or lithium or the like.

This particular reaction then makes it possible to obtain, in a singlestep (the polymerisation and neutralisation being simultaneous), agrinding aid and/or dispersing agent in aqueous suspension of mineralmaterials.

These aqueous suspensions of mineral particles have a high concentrationof mineral materials and have a Brookfield viscosity which is low andstable over time, even without stirring.

This aim is achieved by virtue of the method according to the invention,that is to say using phosphorous acid and/or its salts or sodiumhypophosphite and by neutralisation during the polymerisation of theethylenically unsaturated monomers by continuously adding, first of all,bases such as sodium hydroxide, potassium hydroxide or lithium hydroxideand then alkaline earth bases such as calcium hydroxide, magnesiumhydroxide, calcium oxide or magnesium oxide.

Thus one of the aims of the invention is the development of the saidmethod making it possible to obtain polymers in solution in a singlestep.

Another aim of the invention is to provide a grinding aid and/or adispersing agent in aqueous suspension of mineral materials making itpossible to arrive at aqueous dispersions of mineral materials whichhave a high concentration of mineral material and have a Brookfieldviscosity which is low and stable over time, even without stirring.

In addition another aim of the invention is to provide a sequestringagent or antiscaling agent or mineral scale inhibitor and/orincrustation inhibitor when the molecular weight of the saidhomopolymers and/or copolymers is sufficiently low to be suited to thesaid application.

In addition to these aims, an additional object of the invention is toobtain a fluidising agent for aqueous suspensions used as drillingfluids or to develop a stabiliser for aqueous suspensions of zeolites aswell as to obtain an antiscaling agent.

In addition, another aim of the invention relates to the mineral aqueoussuspensions obtained by the use of the said agents.

Finally, another aim of the invention relates to the use of thesemineral aqueous suspensions in the fields of the filling and coating ofpaper as well as paint, ceramics, detergents and drilling mud.

Thus the method according to the invention of obtaining homopolymersand/or copolymers, in aqueous solution, of ethylenically unsaturatedmonomers is characterised by the use of phosphorous acid and/or itssalts or sodium hypophosphite and by neutralisation during thepolymerisation of the ethylenically unsaturated monomers by thecontinuous addition, first of all, of bases such as sodium hydroxide,potassium hydroxide or lithium hydroxide and then alkaline earth basessuch as calcium hydroxide, calcium oxide, magnesium hydroxide ormagnesium oxide.

The ethylenically unsaturated monomer or monomers is (are) chosen fromamongst at least one of the ethylenically unsaturated anionic monomersor comonomers such as acrylic and/or methacrylic, itaconic, crotonic orfumaric acid, maleic anhydride or isocrotonic, aconitic, mesaconic,sinapinic, undecylenic or angelic acid, acrylamido methylpropanesulphonic acid (referred in the remainder of the description asAMPS) or sodium methallylsulphonate or possibly chosen from amongst theethylenically unsaturated non-ionic comonomers such as acrylamide and/ormethacrylamide.

The ethylenically unsaturated monomer or monomers is (are)preferentially chosen from amongst acrylic or methacrylic acid and,highly preferentially, the invention uses solely acrylic acid.

In the method according to the invention, the homopolymerisation orcopolymerisation reaction, and whatever the ratio by weight of themonomers, is effected by the use of phosphorous acid and/or its salts orsodium hypophosphite in a quantity determined according to the molecularweight required for the polymer, possibly in the presence of all or someof the water necessary for obtaining a homogenous solution.

All or some of the quantity of the said phosphorous acid and/or itssalts or of the said sodium hypophosphite can be introduced completelyat the bottom of the polymerisation tank or added throughout thepolymerisation at the same time as the other additions.

These other additions, which can be chosen from amongst thepolymerisation initiators well known to persons skilled in the art suchas in particular hydrogen peroxide alone or in a mixture with metallicsalts, for example iron or copper, tert-butyl hydroperoxide, or sodiumor potassium persulphates, and the like.

The total quantity of phosphorous acid and/or its salts or sodiumhypophosphite used in the method according to the invention is greaterthan or equal to 0.5% by weight with respect to the total mass of themonomer or monomers making up the polymer according to the invention.

In the method according to the invention, the bases used are chosen fromamongst sodium hydroxide, potassium hydroxide or lithium hydroxide.

They can be added in solution form but also in the form of pellets or inpowder form.

The alkaline earth bases used are chosen from amongst calcium hydroxide,calcium oxide, magnesium hydroxide or magnesium oxide.

The latter can be added in suspension form or in the form of a powderbut also in the form of salts of the corresponding anionic monomers suchas in particular in the form of calcium and/or magnesium acrylate ormethacrylate.

It should also be noted that, in the method according to the invention,the molecular weight of the required copolymer is not only a function ofthe quantity of initiators used but also the level of phosphorusinvolved as well as the concentration of the medium.

The polymerizate obtained can also be processed by any known means inorder to eliminate the water therefrom and isolate it in the form of afine powder and to use it in this form.

According to a variant of the invention, the polymers in solutionaccording to the invention obtained by the method according to theinvention and intended to be used as a grinding aid and/or dispersingagent, as a sequestring agent or scale and/or incrustation inhibitor oras an agent for fluidising aqueous solutions such as drilling fluids oras a zeolite stabilising agent can subsequently be fractionated byfractionation means well known to persons skilled in the art.

The polymers according to the invention are characterised in that theyare obtained by the method according to the invention.

In addition they are characterised in that the degree of neutralisationof the active acid sites is between 40% and 90%, limits included, foralkali ions such as sodium, potassium or lithium, and between 10% and60%, limits included, for alkaline earth ions such as calcium andmagnesium.

The homopolymers and/or copolymers intended to be used according to theinvention as a dispersing agent and/or grinding aid or a fluidiser fordrilling muds or as a stabiliser for zeolite suspensions in detergentcompositions or generally have a molecular weight in terms of M_(w)weight between 2000 and 16,000, preferentially between 3500 and 6500,determined by aqueous GPC, for which the standards, used as references,belong to a series of sodium polyacrylates sold by the company PolymerStandards. Service under the names PSS-PAA varying from 18K to 2K.

Likewise, when the polymer and/or copolymer according to the invention,obtained by the method of the invention is used in the treatment ofindustrial and/or domestic water for the purpose of conferring forexample antiscaling and anticorrosion effects on these media or is usedin the field of reverse osmosis and ultrafiltration for the purpose ofsequestring the cations present, its molecular weight in terms of M_(w)weight is between 2000 and 10,000, determined according to the same GPCmeasuring method as described above.

In practice the operation of dispersing of the mineral substance to bedispersed consists of preparing under stirring an aqueous solution ofthe dispersion agent according to the invention into which there isintroduced the mineral substance to be dispersed, which can have highlydiverse origins, such as natural or synthetic calcium carbonate,dolomites, calcium sulphate, titanium dioxide or lamellar pigments suchas for example mica or kaolin, that is to say all the mineral substanceswhich must be put in suspension and dispersed in order to be useable inapplications as diversified as the coating of papers, the pigmentationof paints, ceramics, drilling muds or detergents.

Likewise, in practice, the operation of grinding the mineral substanceto be refined consists of grinding the mineral substance with a grindingbody into very fine particles in an aqueous medium containing thegrinding agent. First of all an aqueous suspension of the mineralsubstance to be ground is formed, whose grains have an initial size ofno more than 50 microns at the required concentration.

The grinding body with a granulometry advantageously between 0.20 and 4millimetres is added to the suspension of the mineral substance to beground. The grinding body is in general in the form of particles andmaterials as diverse as silicon dioxide, aluminium oxide, zirconiumoxide or mixtures thereof, as well as high-hardness synthetic resins,steels or others. An example of a composition of such a grinding body isgiven by the patent FR 2 303 681, which describes grinding elementsformed by 30 to 70% by weight zirconium oxide, 0.1 to 5% aluminium oxideand 5 to 20% silicon dioxide. The grinding body is preferably added tothe suspension in a quantity such that the ratio by weight between thisgrinding material and the mineral material to be ground is at least 2/1,this ratio preferably being between the limits 3/1 and 5/1.

The mixture of the suspension and grinding body is then subjected to themechanical action of stirring, such as the one which occurs in aconventional microelement grinder.

The grinding aid and/or dispersing agent according to the invention isalso introduced into the mixture formed by the aqueous suspension ofmineral substances and by the grinding body at the rate of 0.2 to 2% byweight of the dried fraction of the said polymers with respect to thedry mass of the mineral substance to be refined.

The time required for arriving at an excellent degree of fineness of themineral substance after grinding varies according to the nature andquantity of the mineral substances to be ground, and according to thestirring mode used and the temperature of the medium during the grindingoperation.

The scope and advantage of the invention will be perceived more clearlyby means of the following examples, which are not limitative:

EXAMPLE 1

The purpose of this example is to illustrate the method, according tothe invention, of obtaining acrylic acid homopolymers or copolymers bythe addition, throughout the polymerisation reaction, of neutralisationagents commencing with the base corresponding to the alkali ion.

To do this, in a polymerisation reactor previously heated and filledwith a load composed of water, phosphorous acid and the requiredquantity of soda for neutralising this acid, or sodium hypophosphite,the various following tests were carried out.

Test No 1:

In a two-litre glass reactor equipped with stirring, a thermometer and acooling system, a load referred to as a tank bottom was prepared at roomtemperature, composed of 104 grams of water, 43.9 grams of soda at 50%and 45 grams of 97% phosphorous acid.

During the rise in temperature of the tank bottom, four loads to beintroduced during the polymerisation were prepared.

For this purpose, 450 grams of 100% acrylic acid were introduced into afirst beaker, into a second beaker 25 grams of hydrogen peroxide at 130volumes and 80 grams of water, into a third beaker 350 grams of soda at50% and finally into a fourth beaker 70 grams of calcium hydroxide and180 grams of water.

The hydrogen peroxide and acrylic acid were added separately andcontinuously during the two hours of polymerisation.

The soda contained in the third beaker was added proportionally to theacrylic acid and continuously. When all the soda was introduced, thelime contained in the fourth beaker was in its turn added until the endof the introduction of the acrylic acid.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 70% by sodium and 30% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 4400 determined according to the GPC method citedabove.

Test No 2:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the quantity of hydrogen peroxide, which was multiplied by0.68.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 70% by sodium and 30% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 5000 determined according to the GPC method citedabove.

Test No 3:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the quantity of hydrogen peroxide, which was multiplied by0.60.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 70% by sodium and 30% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 6200 determined according to the GPC method citedabove.

Test No 4:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the quantity of hydrogen peroxide, which was multiplied by0.15.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 70% by sodium and 30% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 7200 determined according to the GPC method citedabove.

Test No 5:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the quantity of phosphorous acid and the quantity of sodapresent in the tank bottom, which were multiplied by 0.84.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 70% by sodium and 30% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 5500 determined according to the GPC method citedabove.

Test No 6:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the quantity of phosphorous acid which was multiplied by1.10 and the quantity of soda present in the tank bottom, which wasmultiplied by 1.10.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 70% by sodium and 30% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 3800 determined according to the GPC method citedabove.

Test No 7:

In a two-litre glass reactor equipped with stirring, a thermometer and acooling system, a load referred to as a tank bottom was prepared at roomtemperature, composed of 104 grams of water, 43.9 grams of soda at 50%and 45 grams of 97% phosphorous acid.

During the rise in temperature of the tank bottom, five loads to beintroduced during the polymerisation were prepared.

For this purpose, 450 grams of 100% acrylic acid were introduced into afirst beaker, into a second beaker 15 grams of hydrogen peroxide at 130volumes and 65 grams of water, into a third beaker 20 grams of sodiumpersulphate and 60 grams of water, into a fourth beaker 237 grams ofsoda at 50% and finally into a fifth beaker 226 grams of magnesiumhydroxide at 40% in water.

The soda contained in the fourth beaker was added continuously duringthe first hour of polymerisation at the same time as the hydrogenperoxide whilst the magnesium hydroxide contained in the fifth was addedcontinuously during the second hour of polymerisation at the same timeas the persulphate solution. The acrylic acid was added continuouslyduring the two hours.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 3800 determined according to the GPC method citedabove.

Test No 8:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 7 with theexception of the use of a single catalyst, namely 20 grams of sodiumpersulphate in 120 grams of water.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 8600 determined according to the GPC method citedabove.

Test No 9:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 7 with theexception of the quantity of sodium persulphate, diluted to 7% in water,which was multiplied by 0.30, and with the exception of the quantity ofhydrogen peroxide, diluted to 12% in water, which was multiplied by0.66.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 10,000 determined according to the GPC methodcited above.

Test No 10:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 9 with theexception of the quantity of hydrogen peroxide, diluted to 12.5% inwater, which was multiplied by 0.30.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 12,600 determined according to the GPC methodcited above.

Test No 11:

In a two-litre glass reactor equipped with stirring, a thermometer and acooling system, a load referred to as a tank bottom was prepared at roomtemperature, composed of 104 grams of water and 11.3 grams of sodiumhypophosphite crystallised with one molecule of water.

During the rise in temperature of the tank bottom, six loads to beintroduced during the polymerisation were prepared.

For this purpose, 450 grams of 100% acrylic acid were introduced into afirst beaker, into a second beaker 15 grams of hydrogen peroxide at 130volumes and 65 grams of water, into a third beaker 10 grams of sodiumpersulphate and 70 grams of water, into a fourth beaker 237 grams ofsoda at 50%, into a fifth beaker 226 grams of 40% magnesium hydroxide inwater and into a sixth beaker 33 grams of sodium hypophosphitecrystallised with one molecule of water diluted in 40 grams of water.

The soda contained in the fourth beaker was added during the first hourof polymerisation at the same time as the hydrogen peroxide whilst themagnesium hydroxide contained in the fifth was added continuously duringthe second hour of polymerisation at the same time as the sodiumpersulphate.

The acrylic acid and sodium hypophosphite were added continuously andseparately throughout the polymerisation.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 2400 determined according to the GPC method citedabove.

Test No 12:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 11 except for thequantity of sodium hypophosphite in the tank bottom, which wasmultiplied by 0.59, and that added continuously, which was multiplied by0.62. Finally, the initiator consisted solely of 20 grams of hydrogenperoxide at 130 volumes diluted in 140 grams of water. This solution wasadded continuously during the two hours of polymerisation.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 5500 determined according to the GPC method citedabove.

Test No 13:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 11 except for thequantity of sodium hypophosphite in the tank bottom, which wasmultiplied by 0.59, and that contained in the sixth beaker, which wasmultiplied by 0.62.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 6000 determined according to the GPC method citedabove.

Test No 14:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 11 except for thequantity of sodium hypophosphite in the tank bottom, which wasmultiplied by 0.40, and that contained in the sixth beaker, which wasmultiplied by 0.42.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 8350 determined according to the GPC method citedabove.

Test No 15:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 11 except for thequantity of sodium hypophosphite in the tank bottom, which wasmultiplied by 3.98, and that contained in the sixth beaker, which waszero, and finally with the exception of the quantity of hydrogenperoxide contained in the second beaker, which was multiplied by 0.66,and the quantity of sodium persulphate contained in the third beaker,which was multiplied by 0.60.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 9700 determined according to the GPC method citedabove.

Test No 16:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 12 except for thequantity of soda used, which corresponded to a 40% neutralisation of theactive acid sites and that of magnesium hydroxide, which corresponded toa neutralisation of 60% of the active acid sites.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 40% by sodium and 60% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 4300 determined according to the GPC method citedabove.

Test No 17:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 16 except for thequantity of magnesium hydroxide, which was multiplied by 0.416.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and magnesium polyacrylate partiallyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 25% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 5000 determined according to the GPC method citedabove.

It should be noted in this test that, for measuring the molecular weightby GPC, the polymer was completely neutralised, 50% by the sodium and50% by the magnesium.

Test No 18:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 4, with theexception of the quantity of hydrogen peroxide, which was multiplied by4.08, and with the exception of the quantity of soda used, whichcorresponded to an 80% neutralisation of the active acid sites, and thatof calcium hydroxide, which corresponded to a 20% neutralisation of theactive acid sites.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 80% by sodium and 20% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 6000 determined according to the GPC method citedabove.

Test No 19:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 12, with theexception of the quantity of calcium hydroxide used which correspondedto a neutralisation of 25% of the active acid sites and that ofmagnesium hydroxide, which corresponded to a neutralisation of 25% ofthe active acid sites, these two alkaline earth hydroxides being addedduring the second hour of polymerisation.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium, magnesium and calcium polyacrylatetotally neutralised in a ratio corresponding to a neutralisation of theactive acid sites equal to 50% by sodium, 25% by magnesium and 25% bycalcium. The molecular weight M_(w) of the polyacrylate thus obtainedaccording to the invention was equal to 5730 determined according to theGPC method cited above.

Test No 20:

In a two-litre glass reactor equipped with stirring, a thermometer and acooling system, a load referred to as a tank bottom was prepared at roomtemperature, composed of 104 grams of water, 43.9 grams of soda at 50%and 45 grams of 97% phosphorous acid.

During the rise in temperature of the tank bottom, five loads to beintroduced during the polymerisation were prepared.

For this purpose, 225 grams of 100% acrylic acid were introduced into afirst beaker, into a second beaker 15 grams of hydrogen peroxide at 130volumes and 65 grams of water, into a third beaker 10 grams of sodiumpersulphate and 70 grams of water, into a fourth beaker 237 grams ofsoda at 50% and finally into a fifth beaker 233 grams of water and 225grams of acrylic acid at 100% previously having reacted with 226 gramsof magnesium hydroxide at 40% in water.

The soda contained in the fourth beaker was added continuously duringthe first hour of polymerisation at the same time as the hydrogenperoxide whilst the magnesium acrylate contained in the fifth was addedcontinuously during the second hour of polymerisation at the same timeas the persulphate.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 50% by sodium and 50% by magnesium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 9500 determined according to the GPC method citedabove.

Test No 21:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 2, with theexception of the fact that the fourth beaker contained 30% of the totalquantity of acrylic acid and that the latter had previously reacted withlime.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a sodium and calcium polyacrylate completelyneutralised in a ratio corresponding to a neutralisation of the activeacid sites equal to 70% by sodium and 30% by calcium. The molecularweight M_(w) of the polyacrylate thus obtained according to theinvention was equal to 11,500 determined according to the GPC methodcited above.

Test No 22:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the first beaker, which contained 0.400 grams of acrylicacid at 0.100% and 50 grams of acrylamide, the third beaker, whichcontained 312 grams of soda at 50%, and finally the fourth beaker, whichcontained 63 grams of calcium hydroxide.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to an acrylic acid-acrylamide copolymercompletely neutralised by the sodium ion and by the calcium ion in aratio corresponding to a neutralisation of the active acid sites equalto 70% by the sodium and 30% by the calcium. The molecular weight M_(w)of the copolymer thus obtained according to the invention was equal to4200 determined according to the GPC method cited above.

Test No 23:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the first beaker, which contained 400 grams of acrylic acidat 100% and 50 grams of AMPS, the third beaker, which contained 331grams of soda at 50%, and finally the fourth beaker, which contained 66grams of calcium hydroxide.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to an acrylic acid-AMPS copolymer completelyneutralised by the sodium ion and by the calcium ion in a ratiocorresponding to a neutralisation of the active acid sites equal to 70%by the sodium and 30% by the calcium. The molecular weight M_(w) of thecopolymer thus obtained according to the invention was equal to 4600determined according to the GPC method cited above.

Test No 24:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 1 with theexception of the first beaker, which contained 400 grams of acrylic acidat 100% and 50 grams of methacrylic acid, the third beaker, whichcontained 343 grams of soda at 50%, and finally the fourth beaker, whichcontained 68 grams of calcium hydroxide.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to an acrylic acid-methacrylic acid copolymercompletely neutralised by the sodium ion and by the calcium ion in aratio corresponding to a neutralisation of the active acid sites equalto 70% by the sodium and 30% by the calcium. The molecular weight M_(w)of the copolymer thus obtained according to the invention was equal to4200 determined according to the GPC method cited above.

Test No 25:

This test was carried out with the same equipment, the same operatingmethod and the same quantities of reagent as Test No 3, with theexception of the soda, which was replaced by potassium hydroxide.

The polymerizate then obtained in a single step was an orangey-yellowsolution corresponding to a potassium and calcium polyacrylatecompletely neutralised in a ratio corresponding to a neutralisation ofthe active acid sites equal to 70% by potassium and 30% by calcium. Themolecular weight M_(w) of the copolymer thus obtained according to theinvention was equal to 5500 determined according to the GPC method citedabove.

EXAMPLE 2

This example relates to the preparation of a suspension of coarsecalcium carbonate subjected to grinding in order to refine it in amicroparticular suspension. For this purpose, a suspension of coarsecalcium carbonate was prepared from a natural calcium carbonate, using:

-   -   for Test No 26 illustrating the reference test, the calcium        carbonate was simply put in suspension in 25% water without the        addition of a dispersant, a dispersion with a concentration of        76% dry matter being impossible to achieve;    -   for Test No 27 illustrating the invention, the polyacrylate of        Test No 1 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 70% sodium and 30%        calcium neutralisation;    -   for Test No 28 illustrating the invention, the polyacrylate of        Test No 2 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 70% sodium and 30%        calcium neutralisation;    -   for Test No 29 illustrating the invention, the polyacrylate of        Test No 3 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 70% sodium and 30%        calcium neutralisation;    -   for Test No 30 illustrating the invention, the polyacrylate of        Test No 4 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 70% sodium and 30%        calcium neutralisation;    -   for Test No 31 illustrating the invention, the polyacrylate of        Test No 5 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 70% sodium and 30%        calcium neutralisation;    -   for Test No 32 illustrating the invention, the polyacrylate of        Test No 6 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 70% sodium and 30%        calcium neutralisation;    -   for Test No 33 illustrating the invention, the polyacrylate of        Test No 7 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 34 illustrating the invention, the polyacrylate of        Test No 8 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 35 illustrating the invention, the polyacrylate of        Test No 9 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 36 illustrating the invention, the polyacrylate of        Test No 10 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 37 illustrating the invention, the polyacrylate of        Test No 11 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 38 illustrating the invention, the polyacrylate of        Test No 12 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 39 illustrating the invention, the polyacrylate of        Test No 13 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 40 illustrating the invention, the polyacrylate of        Test No 14 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 41 illustrating the invention, the polyacrylate of        Test No 15 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 42 illustrating the invention, the polyacrylate of        Test No 16 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 40% sodium and 60%        magnesium neutralisation;    -   for Test No 43 illustrating the invention, the polyacrylate of        Test No 17 partially neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 25%        magnesium neutralisation;    -   for Test No 44 illustrating the invention, the polyacrylate of        Test No 18 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 80% sodium and 20%        calcium neutralisation;    -   for Test No 45 illustrating the invention, the polyacrylate of        Test No 19 completely neutralised by soda, magnesium hydroxide        and calcium hydroxide in a ratio corresponding to a 50%        sodium-25% magnesium-25% calcium neutralisation;    -   for Test No 46 illustrating the invention, the polyacrylate of        Test No 20 completely neutralised by the soda and magnesium        hydroxide in a ratio corresponding to a 50% sodium and 50%        magnesium neutralisation;    -   for Test No 47 illustrating the invention, the polyacrylate of        Test No 21 completely neutralised by the soda and calcium        hydroxide in a ratio corresponding to a 70% sodium and 30%        calcium neutralisation;    -   for Test No 48 illustrating the invention, the acrylic        acid-acrylamide copolymer of Test No 22 completely neutralised        by the soda and calcium hydroxide in a ratio corresponding to a        70% sodium and 30% calcium neutralisation;    -   for Test No 49 illustrating the invention, the acrylic acid-AMPS        copolymer of Test No 23 completely neutralised by soda and        calcium hydroxide in a ratio corresponding to a 70% sodium-30%        calcium neutralisation;    -   for Test No 50 illustrating the invention, the acrylic        acid-methacrylic acid copolymer of Test No 24 completely        neutralised by soda and calcium hydroxide in a ratio        corresponding to a 70% sodium-30% calcium neutralisation;    -   for Test No 51 illustrating the invention, the polyacrylate of        Test No 25 completely neutralised by potash and calcium        hydroxide in a ratio corresponding to a 70% potassium-30%        calcium neutralisation.

For each test, an aqueous solution was prepared from calcium carbonatecoming from the Orgon (France) deposit, with a mean diameter of around50 micrometres.

The aqueous suspension had a dry matter concentration of 76% by weightwith respect to the total mass with the exception of the reference test,for which the suspension had a dry matter concentration of 25% by weightwith respect to the total mass.

The grinding aid agent was introduced into this suspension in thequantities indicated in the following table, expressed as a percentageby dry weight with respect to the weight of dry calcium carbonate to beground.

The suspension circulated in a grinder of the Dyno-Mill type with afixed cylinder and rotating impeller, whose grinding body consisted ofcorundum balls with a diameter in the range from 0.6 millimetres to 1.0millimetres.

The total volume occupied by the grinding body was 1150 cubiccentimetres whilst its weight was 2900 g.

The grinding chamber had a volume of 1400 cubic centimetres.

The circumferential speed of the grinder was 10 metres per second.

The calcium carbonate suspension was recycled at the rate of 18 litresper hour.

The outlet of the Dyno-Mill grinder was provided with a 200 micron meshseparator for separating the suspension resulting from the grinding andthe grinding body. The temperature during each grinding test wasmaintained at approximately 60° C.

At the end of the grinding (To), a sample of the pigmentary suspensionwas recovered in a flask. The granulometry of this suspension (% of theparticles less than 1 micrometre) was measured by means of a Sedigraph5100 granulometer from Micromeritics.

The Brookfield viscosity of the suspension was measured by means of aBrookfield viscometer type RVT, at a temperature of 20° C. and speeds ofrotation of 10 revolutions per minute and 100 revolutions per minutewith the appropriate spindle.

After a residence time of 8 days in the flask, the viscosity of thesuspension was measured by introducing, into the unstirred flask, theappropriate spindle of the Brookfield viscometer type RVT, at atemperature of 20° C. and speeds of rotation of 10 revolutions perminute and 100 revolutions per minute (viscosity BS=before stirring).

The same viscosity measurements were also made once the flask had beenstirred and constitute the AS (after stirring) viscosity results.

All these experimental results are set out in Tables 1 and 1a below,which also indicate the consumption, as a percentage by weight, ofgrinding-aid agent used for obtaining the granulometry indicated:BROOKFIELD VISCOSITY OF THE SUSPENSION (at 20° C. in mPa · s) DRY MATTERGRINDING-AID 8 days 8 days CONCEN- AGENT T0 BS AS TRATION ConsumptionGRANULOMETRY 10 rev/ 10 rev/ 10 rev/ TEST OF THE Polymer of agent as a(% particles <1 min-100 min-100 min-100 N^(o) SUSPENSION Test N^(o)M_(w) dry/dry % μm) rev/min rev/min rev/min 26 25 — — — — 800-45020,000-2500   1200-650  27 76 1 4400 1.27 80 1800-670  4555-10101860-680  28 76 2 5000 1.24 80 2090-660  7490-1370 2790-900  29 76 36200 1.26 80 1670-530  4555-1070 1880-685  30 76 4 7200 1.20 75.32300-775  6080-1210 1810-635  31 76 5 5500 1.30 80 2200-700  6000-12002000-700  32 76 6 3800 1.25 80 1900-690  5500-1100 1920-690  33 76 73800 1.26 76 1790-590  4400-1040 1400-460  34 76 8 8600 1.16 67 780-3155600-1310 840-330 35 76 9 10,000 1.26 72 2680-860  11,800-1880  3230-1090 36 76 10 12,600 1.25 65 1550-580  16,800-2410   2240-790  3776 11 2400 1.22 80 5055-1470 4660-3400 10,860-2500   38 76 12 5500 1.2877 2200-750  6400-1900 5500-1545 39 76 13 6000 1.32 70 1230-500 6000-1200 1300-525  40 76 14 8350 1.34 68 2410-820  15,500-2340  2400-900  41 76 15 9700 1.28 73 7000-1600 28,200-3600   16,400-2600   4276 16 4300 1.40 72 3000-1100 9000-2700 4200-1200 43 76 17 5000 1.25 782500-830  7000-2500 3500-1000 44 76 18 6000 1.25 77 2600-800  7500-15002200-700  45 76 19 5730 1.12 80 3500-1000 7500-1500 3700-1150 46 76 209500 1.27 74 3080-930  11,080-1680   3100-1040 47 76 21 11,500 1.20 724600-1400 16,800-2150   2920-1075 48 76 22 4200 1.25 77 2200-800 6500-1300 2200-730  49 76 23 4600 1.25 80 1850-700  4700-1070 1930-710 50 76 24 4200 1.32 80 2500-750  7800-1800 2600-850  51 76 25 5500 1.1580 5000-1500 12,000-3000   6800-1850BS: Measurement of the viscosity before stirring of the suspensionAS: Measurement of the viscosity after stirring of the suspensionTest N^(o) 26 is the reference testTests 27 to 39 relate to the inventionTests 40 to 51 relate to the invention

A reading of Tables 1 and 1a show the efficacy of the polymers of theinvention, obtained by the method according to the invention, as agrinding aid of an aqueous suspension of mineral materials with a highconcentration of dry matter.

EXAMPLE 3

This example relates to the use of an aqueous suspension of calciumcarbonate according to the invention in the field of paper. This examplealso relates to the use of polymers according to the invention as waterretaining agent. For this purpose, different 100% calcium carbonatecoating colors are prepared and are composed of:

-   -   100 parts, expressed as dry matter, of an aqueous suspension of        calcium carbonate to be tested,    -   10 parts, expressed as dry matter, of a styrene-butadiene latex        sold by Dow under the name “DL 950”,    -   0.25 parts, expressed as dry matter, of co-binder sold by Coatex        under the name Rheocoat™ 35.

The various following tests are carried out:

Test No 52:

This test illustrates the prior art and implements a carbonate calciumsuspension sold by Omya under the name Hydrocarb™ 90 OG.

Test No 53:

This test illustrates the invention and implements a carbonate calciumsuspension with the same above-cited granulometry and containing thesame polymer as the invention of test No 6.

For both tests, the water-retention of the coating colors is determinedby the method described hereafter.

The paper coating color to be tested is subjected to a pressure of 100psi (7 bars) in a standard cylinder, equipped with a surface of thefilter paper type capable of allowing water to pass.

After 20 minutes, the volume of water collected is measured in ml.

The lower the volume of water collected at the end of 20 minutes, thebetter is the retention.

To do this, use is made of an “API Fluid Loss Measurement” filter press(FIG. 1/1) from Baroïd, which is composed essentially of a clamp (1)provided with a clamping screw (2) for locking the three parts of thefilter body (3).

This body (3) is composed of:

-   -   a base (4) with a hole provided with a nozzle through which the        filtrate flows. This base (4) supports a metallic sieve (5) with        a mesh of 60 to 80, on which is placed the 90 mm diameter filter        paper (6) (Whatman™ No 50), the equivalent of which is the        DURIEUX BLEU™ No 3 type,    -   a cylinder with an inside diameter of 76.2 mm and a height of        128 mm,    -   a cover (7) provided with a compressed gas inlet, whose seal        with the cylinder is provided by means of a flat joint (8), of        the same type as those (9) placed on the base (4).

To use the filter press, the following are fitted in the followingorder:

-   -   the joint (9) on the base (4)    -   the sieve (5) on the joints (9)    -   the filter paper (6) on the sieve (5)    -   the second joint (10) on the filter paper (6)    -   and the cylinder is fitted on the base (4) before locking the        bayonet system.

Then it is filled with the coating color to be tested (approximately 480g up to 3 cm from the top of the cylinder) before placing the cover (7)on the cylinder, interposing a joint (8).

Then the assembly is placed in the clamp (1) and is locked by means ofthe clamping screw (2), and then a graduated tube (12) is arrangedunderneath the nozzle.

A pressure of 7 bars is applied, simultaneously triggering achronometer.

After 20 minutes the volume of fluid collected in the test tube (12) isnoted. The accuracy of the result obtained is ±0.2 ml.

The results of the water-retention measurement obtained, according tothe method described above in the description, are set out in Table 2below.

The results of the measurements of Brookfield viscosity determined at 10and 100 revolutions per minute at 25° C. by means of a Brookfieldviscometer type DV-1 equipped with the appropriate spindle also appearin Table 2. TABLE 2 Prior art Invention Test n^(o) 52 53 FORMULATIONS:Pigments: Calcium carbonate Hydrocarb ™ 90   100 OG Calcium carbonateaccording to   100 the invention Latex: DL 950   10   10 Coliants:Rheocoat ™ 35    0.25    0.25 Solid content (%)   66.2   66.2 pH    9   9 Brookfield viscosities  10 rev/min 2 700 3 570 (mpa · s) 100 rev/min  632   715 Water-retention API Vol in 20    3.25    2.65 (ml) min

The reading of Table 2 shows the use of aqueous suspensions of mineralmaterials according to the invention in the field of paper as well asthe use of polymers according to the invention as water retaining agentin the paper making industry.

EXAMPLE 4

This example relates to the use of aqueous suspensions of mineralmaterials according to the invention in a water-based interior mattpaint. For this purpose, the efficiency as a dispersant of the polymersof the invention contained in the aqueous suspensions of mineralmaterials of the invention implemented in a interior matt paint.

Thus, for the tests No 54 and 55, 0.12% by dry weight of the testeddispersant relative to the total weight of a same water-based matt paintformula was added under agitation to a container which already held144.5 g of water and 1 g of 28% ammonia.

After agitating for a few seconds, once the polymer to be tested hasbeen added to the water containing ammonia, the other constituents ofthe said water-based matt paint were added in succession, these being: 2g of a biocide, marketed by Troy under the name of MERGAL ™ K6N 1 g ofan anti-foaming agent marketed by Henkel under the name of NOPCO ™ NDW69 g of rutile titanium oxide marketed by Millenium under the name TIONARL 68 311.4 g of natural calcium carbonate marketed by Omya under thename of DURCAL ™ 5 204 g of natural calcium carbonate marketed by Omyaunder the name of HYDROCARB ™ 154.7 g of a styrene-acrylic binder indispersion, marketed by Rhodia under the name of RHODOPAS ™ DS 910 10 gof monoethylene glycol 10 g of coalescing agent marketed by EastmanChemicals under the name TEXANOL 1.3 g of 28% animonia 10.0 g of athickening agent marketed by Coatex under the name RHEO ™ 3000 quantityto make up 1000 g - water.

The various tests are:

Test No 54:

This test is the reference test and illustrates the prior artimplementing a sodium polyacrylate marketed by Coatex under the nameCOATEX P50.

Tests No 55:

This test illustrates the invention and implements the polymer of theinvention of test No 6.

For each of these tests, after agitating the aqueous composition made upin this way for a few minutes, the Brookfield viscosities of thedifferent compositions are measured at 25° C. and at 10 revolutions perminute and 100 revolutions per minute using a standard RVT Brookfieldviscometer fitted with the requisite spindle.

The rheological stability of the formulae over time and in terms oftemperature is determined by measuring the Brookfield viscosities at 10revolutions per minute and 100 revolutions per minute and at 25° C. ofthese same formulae after storing at ambient temperature withoutagitation for 24 hours and for one week.

All these results are set out in table 3 below: TABLE 3 BROOKFIELDVISCOSITY OF THE PAINT T = 0 T = 24 hours T = 1 week, 25° C. DISPERSANT10 rev/min- 10 rev/min- 10 rev/min- DRY % 100 rev/min 100 rev/min 100rev/min TEST No WEIGHT (mPa · s) (mPa · s) (mPa · s) Prior art 54 0.1213700-3700 17000-4900 19400-5600 Invention 55 0.12 12600-3400 15900-460018200-5050

The reading of table 3 shows the use of aqueous suspensions of mineralmaterials according to the invention in the field of paint.

EXAMPLE 5

The purpose of this example is to illustrate the use of the polymers ofthe invention as an anti-scaling agent in water treatment applications,by measuring the delay in the precipitation of alkaline earths and morespecifically calcium carbonate contained in natural or artificialwaters, saline or not, in the presence of the said polymers.

To this end, for each of the tests, town water containing 5 ppm by dryweight of each of the polymers to be tested is introduced into aone-litre flask provided with a coolant, with the exception of test No56, which is the reference test and in which the town water does notcontain any polymer.

Tests No 57 and 58 illustrate the invention using the copolymersproduced from tests No 6 and 11 respectively.

This water is heated to boiling point and under reflux. At t=0, i.e.when the first ring of bubbles (start of boiling) appears, a 20 ml testsample is taken. This water is immediately filtered on a 0.45 micronMillipore filter then transferred to a 100 ml beaker to be metered withEDTA. For this purpose, a MERCK indicator buffer tablet, reference108430, 3 ml ammonia buffer, is inserted in the beaker and agitated witha magnetic bar before filtering the water. After a few seconds ofagitation, the EDTA 5.10-3 M is tapped using a burette until it is cleargreen in colour. The TH (hydrotimetric titre) obtained is calculated byVolume EDTA tapped×2.5=TH in ° French (1 degree French=10 mg expressedin CaCo₃ per litre of water) and the value obtained is then written TH0. Similarly, samples are taken after 15 and 30 minutes of boiling. TheTH values obtained are then noted TH 15 and TH 30 minutes boiling andare set out in Table 4 below: TABLE 4 TEST ANTI-SCALING No AGENT TH 0 TH15 TH 30 REFERENCE 56 — 29.4 7.9 6.6 TEST INVENTION 57 Polymer test No 629.5 20.1 15.8 INVENTION 58 Polymer test No 11 29.4 20.1 16.5

The efficiency of the polymers of the invention obtained using themethod of the invention as an anti-scale agent can be seen from table No4.

EXAMPLE 6

This example relates to chlorinated alkaline formulae used, amongstother things, as a bleaching and disinfecting agent in detergents butcould also relate to other bleaching agents commonly used in detergency.

More specifically, the purpose is to demonstrate the fact that the useof the polymers of the invention as an anti-scale and dispersing agentin these formulae is not detrimental to the stability of a chlorinatedalkaline composition in terms of a decrease in the chlorometric ratewhich would imply a loss in efficiency of the hypochlorite solutioncontained in the detergent compound.

In this case, for each test, 29.35 grams of bleach with a chlorometricrate of 36.96 and 15 grams of 50% soda are added under agitation to a200 ml beaker containing 50.65 grams of water.

Once this mixture has homogenised, 5 grams of the polymer to be testedare added except in the case of test No 59, which is the reference testand to which no polymer is added.

After waiting for the mixture to cool, 10 ml of the said mixture arediluted in 100 ml of water.

After dilution, the hypochlorites present in 20 ml of the dilutedchlorinated alkaline composition are metered.

The hypochlorites are metered using the Bunsen method based on theprinciple of oxidation of the iodide ions by the hypochlorite ions. Theiodine thus released is titrated by a solution of 0.1 N sodiumthiosulphate which enables the chlorometric rate of the chlorinatedalkaline composition to be derived by a process of calculation.

The chlorometric rate (° CL) for the 20 ml test sample is worked out asfollows:${{^\circ}CL} = {\frac{{Volume}\quad{of}\quad{sodium}\quad{thiosulphate}}{20} \times 11.2}$

The value obtained for the reference test No 59 is then used as areference value and represents 100% of hypochlorite present in theformula.

The different tests conducted are:

Test No 59:

Reference test with no polymer.

Test No 60:

Test illustrating the prior art using a sodium polyacrylate produced byany method of the prior art and having a molecular weight M_(w) equal to5500.

Test No 61:

Test illustrating the invention and using the polymer of test No 2.

For each of these tests, the chlorometric rate is determined by the samemetering method after 24 hours and 8 days.

The results in percentage residual hypochlorite as compared with thereference are set out in table 5 below: TABLE 5 T0 24 hours 8 days TESTNo POLYMER (%) (%) (%) REFERENCE 59 — 100 100 99.5 TEST PRIOR ART 60Sodium 100 98.4 90.6 polyacrylate of M_(w) = 5500 INVENTION 61 Polymerof 100 99.5 95.0 test No 2

A reading of Table 5 above shows the change in the chlorometric numberof each of the solutions and illustrates the fact that the polymersaccording to the invention obtained by the method of the invention makeit possible not to destabilise the chlorometric number of thechlorinated alkaline composition.

EXAMPLE 7

This example concerns the use of a polymer according to the invention inthe field of ceramics.

For this purpose, tests are first of all carried out on the efficacy ofthe polymer as a clay dispersant for slip and then tests of efficacy asan agent for grinding the clays used in the field of ceramics.

Test of Efficacy as a Dispersant:

For this purpose, untreated water and the polymer according to theinvention to be tested were weighed in a 500 ml beaker stirred by meansof a 70 mm diameter blade. Then the clay was added in a shower anddispersion was carried out for 20 minutes at 1200 rev/min. Raw materialsQuantity (g) Untreated water 300.09 Polymer of Test No 6 1.538 Clay200.00 Quantity of dispersant 0.30% dry/dry

The slip thus produced was transferred to a flow viscometer of theLehmann viscometer type. A first viscosity measurement was carried outat time T₀ and then a second at time T_(10 min).

The flow times read were 27.4 secs for the measurement at time T₀ and31.05 for the measurement at T_(10 min). Given that a polymer isacceptable when the flow time at T₀ is less than 30 and the time atT_(10 min) is less than 35, the polymer is perfectly usable for thedispersion of clay for slip.

Test of Efficacy as a Clay Grinding Agent:

In a 400 ml ceramic jar, 300 g of 16 mm diameter ceramic balls (that isto say approximately 35 balls) were weighed. Next the clay and then theuntreated water and finally the polymer according to the invention wereweighed. The jar was closed and was placed on the grinder. Next grindingwas carried out for 10 minutes at 560 rev/min. The grinder was finallystopped and a Ford No 4 beaker was filled with the slip. Raw materialsQuantity (g) Clay 133.33 Untreated water 200.06 Polymer of Test No 61.367 Quantity of dispersant 0.40% dry/dry

The flow time was measured with the Ford No 4 beaker (T₀), the slip waskept and a second measurement was carried out at time T_(5 min). Theflow time at T₀ was 22.5 secs and that at T_(5 min) was 26.7. Giventhat, in order to be useable for grinding, the polymer must make itpossible to obtain a slip with a flow time T₀ of less than 25 secs andan increase in the flow time at 5 min of less than 25% of the value attime T₀, in order to allow complete and rapid discharge of industrialgrinders. The polymer can therefore be used as a clay grinding agent foran application in ceramics.

EXAMPLE 8

This exemple concerns the use of a polymer according to the invention asthinning agent of a drilling fluid.

1) Operating Method:

In a Hamilton Beach bowl, synthetic sea water was weighed. This wasstirred using the Hamilton Beach and the different clays and powderswere added in a shower, stirring for 10 minutes between each addition.The pH was adjusted to 10.5 using 50% sodium hydroxide. The polymeraccording to the invention to be tested was added and stirring wascarried for a further 10 minutes. The pH was once again adjusted to 10.5using 25% sodium hydroxide. The mud obtained was poured into a rollingcell and was placed in the temperature rolling oven and left to age forone night at 150° C. with rolling (approximately 70 revolutions/minute).

2) Formulation: Raw materials Quantity (g) Sea Water 375.9 Swelling clay17.655 Filler clay 10.088 Barytes 277.5 Filtrate reducing agent 5.35Polymer of Test No 16 7.5 Quantity of dispersant 0.96% dry/dry

After rolling, the cell was recooled, the mud was poured into a HamiltonBeach bowl and stirred for 3 mins. At the end of the stirring, therheological parameters of the mud were measured by means of a Fannviscometer. The plastic viscosity (Vp) found was 30 mPa·s, the yieldvalue (Yv) 16 and the 10 secs and 10 min gels were 3.5 and 8 mPa·s. Thepolymer according to the invention therefore makes it possible to obtaina correct viscosity of the mud (Vp) allowing easy pumping and a yieldvalue enabling the cuttings to be well held in suspension. The slightincrease in gel between 10 secs and 10 min allows easy resumption ofpumping after a stoppage of the well.

EXAMPLE 9

This example concerns the use of a polymer according to the invention asa co-builder in detergents with a low phosphate level.

A detergent having the following dry composition was prepared by puttingin a slurry and then atomising against the flow in an atomiser with ahigh-pressure injection head.

Composition: Builder (sodium tripolyphosphate) 17 Co-Builder (polymeraccording to the invention to be 8 tested) Surfactant(n-docecylbenzenesulphonate) 18 Stabiliser (sodium metasilicate) 7Stabiliser (magnesium silicate) 2 Bleaching agent (sodium perborate) 21Bleaching activator 2 Filling agent (sodium sulphate) 25

The detergent was then used for washing a square of soiled cotton, underthe following conditions: Temperature changing from 25 to 65° C.Duration of washing cycle 45 min Hardness of water 300 ppm in CaCO₃equivalent (Ca: Mg = 2/1) Washing powder concentration 10 g/l

The efficacy of the polymer was measured by the mean whiteness(reflectance) of the piece of the cotton. The piece washed with awashing powder in which the polymer according to the invention isreplaced by the filling agent gave a reflectance of 52% whilst with thepolymer of test No 2 according to the invention the reflectance was 56%.This increase represents an increased whiteness afforded by the propertywhich the polymer has to reduce the formation of alkaline-earth saltswhich are insoluble during washing.

1-8. (canceled)
 9. A homopolymer and/or copolymer in aqueous solution,obtained by a method comprising polymerizing one or more ethylenicallyunsaturated monomers in the presence of phosphorous acid and/or itssalts or sodium hypophosphite, wherein during said polymerizing the oneor more ethylenically unsaturated monomers are neutralized by thecontinuous addition of, first, one or more bases selected from sodiumhydroxide, potassium hydroxide or lithium hydroxide, and then one ormore bases selected from calcium hydroxide, calcium oxide, magnesiumhydroxide or magnesium oxide, wherein the degree of neutralization ofthe active acid sites of the one or more ethylenically unsaturatedmonomers is between 40% and 90%, limits included, resulting from theneutralization with one or more ions selected from sodium ion, potassiumion or lithium ion, and wherein the degree of neutralization of theactive acid sites is between 10% and 60%, limits included, resultingfrom the neutralization with one or more ions selected from calcium ionor magnesium ion.
 10. The homopolymer and/or copolymer in aqueoussolution according to claim 9, wherein said homopolymer and/or copolymeris in the completely neutralized form.
 11. The homopolymer and/orcopolymer in aqueous solution according to claim 9, wherein saidhomopolymer and/or copolymer is partially neutralized.
 12. Thehomopolymer and/or copolymer in aqueous solution according to claim 9,wherein said homopolymer and/or copolymer has a molecular weight, M_(w),between 2000 and 16,000, determined by aqueous GPC. 13-18. (canceled)19. Aqueous suspensions of mineral materials containing the homopolymerand/or copolymer solution of claim
 9. 20. (canceled)
 21. A process forgrinding one or more minerals, said process comprising: grinding one ormore minerals in an aqueous medium in the presence of the homopolymerand/or copolymer solution of claim
 9. 22. A process for dispersing oneor more mineral materials, said process comprising: dispersing one ormore mineral materials in an aqueous medium with the homopolymer and/orcopolymer solution of claim
 9. 23. A process for making paper, saidprocess comprising: adding the homopolymer and/or copolymer solution ofclaim 9 with a paper formulation, wherein the homopolymer and/orcopolymer solution acts as a water retaining agent.
 24. A method oftreating water, said method comprising: sequestering or inhibiting theprecipitation and/or incrustation of minerals in an industrial ordomestic water by adding the homopolymer and/or copolymer solution ofclaim 9 with said water.
 25. A method for preventing scale or corrosionin the field of inverse osmosis and ultrafiltration, said methodcomprising: adding the homopolymer and/or copolymer solution of claim 9with a fluid.
 26. A method for treating a drilling fluid, said methodcomprising: adding the homopolymer and/or copolymer solution of claim 9with said drilling fluid.
 27. A method for preventing or treating scale,said method comprising: adding the homopolymer and/or copolymer solutionof claim 9 with a detergent formula to form a mixture, wherein saidmixture has a stable chlorometric rate of one or more hypochloridespresent in said detergent.
 28. A method for dispersing an agent, saidmethod comprising: adding the homopolymer and/or copolymer solution ofclaim 9 with a detergent formula to form a mixture, and dispersing anagent with said mixture, wherein said mixture has a stable chlorometricrate of one or more hypochlorides present in said detergent.
 29. Amethod for stabilizing a zeolite, said method comprising: adding thehomopolymer and/or copolymer solution of claim 9 with a detergentformula to form a mixture, and stabilizing a zeolite with said mixture,wherein said mixture has a stable chlorometric rate of one or morehypochlorides present in said detergent.
 30. A process for preparing anaqueous suspension of one or more mineral materials, said processcomprising: adding the homopolymer and/or copolymer solution of claim 9with a paper, paint, ceramic, drilling fluid or detergent.
 31. Thehomopolymer and/or copolymer in aqueous solution according to claim 12,wherein said homopolymer and/or copolymer has a molecular weight, Mw,between 3500 and 6500.